The broad objectives of this 3-year project are to identify pregnancy-associated proteins in primate endometrium and to obtain basic information about such proteins with respect to hormonal control of their synthesis, their tissue- and species-specificity and their biochemical nature, to isolate them in pure form, to develop a sensitive assay for their determination in tissues and body fluids, and lastly to develop an animal model to study their biological roles and potential for fertility control. We have, during the first project year, identified two pregnancy-associated antigenic proteins, termed antigens A and B, in the human endometrium, and have purified and characterized them. Monospecific antisera against antigen A have been produced in rabbits and sheep. We are in the process of further purifying antigen A. Also we are exploring whether a baboon can be used as a non-human primate to assess the potential use of antigen A for fertility control. In addition efforts are being made to determine whether antigen A-like protein is encountered in a pregnant rat uterus and, if so, whether antigen A plays any role in pregnancy.